CA1221010A

CA1221010A - Vehicle alignment system

Info

Publication number: CA1221010A
Application number: CA000447332A
Authority: CA
Inventors: William C. Hanlon
Original assignee: Firestone Tire and Rubber Co
Current assignee: Bridgestone Firestone Inc
Priority date: 1983-06-13
Filing date: 1984-02-14
Publication date: 1987-04-28
Also published as: KR850000331A; FI841180A0; ZA841313B; DE3467401D1; ES533071A0; FI841180A; ATE30772T1; JPS59230803A; BR8401609A; PT78301B; US4800651A; AR243999A1; ES8504384A1; DK287184D0; NO840753L; NZ207141A; EP0128267B1; PT78301A; EP0128267A1; DK287184A

Abstract

ABSTRACT OF THE DISCLOSURE

An apparatus and method for aligning axles with respect to the frame of a vehicle and for determining wheel camber thereof. The apparatus for determining the align-ment of a vehicle axle of a vehicle having at least one wheel comprises: a first reference means adapted to be fi-xedly attached to said vehicle; a second reference means adapted to be fixedly attached to said wheel; and measuring means adapted to measure the distance between a point on said first reference means to a point on said second reference means.

Description

1~2~01~

VEHICLE AL I GNMENT SYSTEM

Background of ~he Invention 1. F~eld of the Invention Thi8 invention relate~ to an alignment means and more particularly to an alignment means adapted to align vehicle axle~ and wheels. Specifically, the in~tant invention relates to an alignment means employing a fixed reference located relative to ~he frame of a vehicle and a means for establishing the centerline of the axle of the vehicle whereby the distance between the fixed reference point and the centerline of the axle may be measured in order to determine alignment of the axle with re~pect to the frame. In addition, the camber of the - wheel~ may be determined by using level means.

2. Description of the Prior Art Alignment means for aligning vehicle wheels are well-known in the art as evidenced by British Patent No.
778,838 and numerous advertisements found ln trade publications such a6 the Modern Tire Dealer at Yolume S3, Number 7, June of 1982 at page 3; Volume 63, Number 4, April of 1982 at page 13; Volume 62, Number 2, February of 1981 at page 16; Volume 63, Number 9, August of 1982 at page 31; Volume 63, Number 7, June of 1982 at page 44; Volume 62, Number 4, April of 1981 at page 34; Volume 63, Number 11, Sept~mber of 1982 at page 10;
Vol~me 62, Number 8, July of 1981 at page 6; Volume 63, Number 8, July of 1982 at page 43.

The~e prior art deviceR typically utilize a wheel clamp affixed to the wheel of a vehicle, ~aid wheel clamp having ~ensors which are utilized to dstermine the ~2~

orientation of the wheel and thus the alignment of the wheel/tire combination.

The apparatu~ employed by the prior art is t~pically i~tended to be u~ed in a truck repair facility and conventionally employs rather sophisticated equipment and specialized device~ in order to align vehicle wheels.

It has been recognized, as shown in the Modern Tire Dealer, Volume 63, Number 7, June of 1982 at page 31, that alignment of the drive axles of trucks with respect to their frame member~ i5 extremely important. Rear axle mi alignment can ~reate Ride forces resulting in uneven wear on ~he steering axle tire~ as well as drive axle tires.

The two most ~ommon faults are drive axles that are not perpendicular to the chassis centerline and drive axles that are not parallel to each other. In either case, drive axle misalignment will not only cause scuffing of the rear tires, but will also put a steady side force on both front tires leading to rapid wear of the front tires. Becauce this front tire wear resembles toe wear~ it is often difficult to p~npoint the actual problem. A typical means for aligning the axle~ of a truck i8 found in the Modern Tire Dealer, Volume 62, Number 7, June of 1981 at page 55. Generally, the loaded truck i~ parked on level ground, preferably using the hand brake or trailer brakes to ~top ~o ride heights will be typical. A plumb bob ~tring i8 then taped to the fendsr of ~he truck in order that the plumb line is centered over the hub when viewed from the ~ide. A tape measure i~ then uced to ~ea~ure the distance from the ~tring to the flange at the top o~ the wheel and i~ again u~ed to measure the di6tance from the 6tring to the ~lange at the bottom of the wheel. The Z~ ~2~ 0 difference in measurements between the measurement at the top oE the flange and the measurement at the bottom of the flange provides an indication of the camber of the wheel.

Axle alignement may be checked in a somewhat simi-lar manner by parking the loaded truck on a flat surface.
A plumb line is then dropped from the point where each end of each axle meets its spring. A comparable point is used at each axle spring junction. The plumb points are then marked on the ground and the truck is moved. The distance between the points is then measured to determine axle alignment.

It has been found that this method of determining truck alignment is somewhat time consuming and yields results which are not sufficiently accurate. The instant invention is intended to remedy these problems by providing a means for quickly determining the alignment of a vehicle to a reasonable degree of accuracy.
Summary of the Invention According to the present invention there is provided a method for determining alignment of a vehicle axle having a first and second end with respect to a frame member of said vehicle comprising the steps of:
a. measuring a first distance from a point related to the centerline of said first end of said axle to a reference line perpendicular to said frame member;
b. measuring a second distance from a point rela-ted to the centerline of said second end of said axle to said reference line perpendicular to said frame member; and ,~ ~5L22~
- 3a c. comparing the measurements of said first and second distances.
According to the present invention, there is also provided a method for determining the alignment of a vehi-cle axle having a wheel mounted on each end thereof with respect to a vehicle frame member comprising the steps of:
a. affixing a first reference member to said vehicle frame member;
b. affixing a second reference member to a first one of said wheels;
c. measuring the distance from a point on said first reference member to a point on said second reference member;
d. affixing a second reference member to a second one of said wheels;
e. measuring the distance from a point on said first reference member to a point on said second reference member on said second one of said wheels; and f. comparing the distance from said first measure-ment with the distance from said second measure-ment.
According to the present invention, there is also provided an apparatus for determining the alignment of a vehicle axle of a vehicle having at least one wheel compri-25 sing:
a. a first reference means adapted to be fixedly attached to said vehicle;
b. a second reference means adapted to be fixedly attached to said wheel; and c. measuring means adapted to measure the distance between a point on said first reference means to a point on said second reference means.

'`,,.~,2P

- 3b -Preferred embodiments will now be described as example without limitative manner having reference the attached drawings, wherein:
Fig. 1 is a simplified perspective view of the drive wheels of a vehicle showing the manner in which the instant invention is employed, Fig 2 is a plan view of a vehicle schematically representing axle position which discloses the manner in which the instant iDventic~n is employe - 4 ~

Fig. 3 i a ~ide view of the rear portion of a vehicle as diæclosed in Fig. 1 of the drawings.

Fig. 4 i~ a cross-sectional view of the reference bar utilized by the ~nætant invention, 6howing the details of construction thereof.

Fig. 5 i8 A perspective view of the w~eel clamp employed by the instant invention.

Fig. S is a ~ide view of the wheel clamp di~closed in Fig. 5 having the camber attachment affixed thereto.

Fig. 7 i~ an enlarged detail of the camber attachment disclosed in Fig. 6 of the drawings, showing the details of construction thereof.

Description ~f an Exemplarv Embodiment Fig. 1 of the drawings 6chematically discloses the rear portion of a conventional truck tractor 11 having frame member~ 12 to which are mounted drive axles 13 and 14. It should be appreciated that although the exemplary embodiment i8 described in connection with a truck tractor, it would be obvious to one 6killed in the art that the instant invention ~ay also be employed with other vehicles requiring alignment, including, but not limited to automobiles, tractors, trailers, etc.

A conventional truck tractor 11 generally comprises two parallel frame member6 de6ignated 1~ to which are affixed the Axle~ supporting the frame members. The frame members 12 12~ 01 0 -- ar~ generally fabricated using jigs and fixtures with the result that the ~rame member~ 12 are parallel to each other.
The axles 13 and 14 are typically mounted to the frame members 12 via ~pring means not shown in Fig. 1 for clarity. The ~xle~ and ~heir ascociated suspension means are conventionally mounted on the frame members 12 by a manual operation without the u~e o~ either jigs or fixtures oftentimes resulting in inaccuracy in the mounting of the axle~ to the frame member~.
Thi6 inaccuracy in mounting can result in either a situation wherein the rear drive axle o the truck is not perpendicular to the frame members of the truck or alternatively, in a tandem axle truck tractor, the situation wherein the rear drive axle~ of the truck tractor are not parallel to each other. Both situations result in ~cuffing of the rear axle tireæ and cause additional wear to the front steering tires.

The instant invention is comprised of two main component~. The first component is the reference bar assembly 16 which provides a reference relating to the orientation of the frame member 12. Specifically, the reference bar assembly 16 provide a reference line extended from the frame members 12 and perpendicular thereto from which measurements may be taken to~the perpendicular line.

The second major component of the instant invention is the wheel a~sembly 26 which i8 adapted to be mounted to the rim of a vehicle wheel. The wheel assembly 26 generally provide~ an extension of the outer edge of the rim of the wheel and has mean~ for allowing the extension of the centerline of the axle having the wheel to which the wheel assembly 26 is mounted.

~22~

Referring now to Fig. 2 of the ~rawin~fi, there :i8 di~closed a schematic plan view of a conventional truck tractor 11 having frame members 12 upon which are mounted rear drive axle~ 13 and 14 and front axle 20, all having wheels affixed thereto.

Mounted on the rear portion o the frame members 12 i8 reference bar 16. Associated with each of he outer wheels of the axles 13, 14 and 20 i8 a bar schematically repre~enting the wheel assembly 26.

10It i~ one of the objects of the instant invention to determine if the axes of the axles 13, 14 and 20 are perpendi-- cular with re6pect to the rame member 12. Accordingly, the reference bar assembly 16 is temporarily affixed to the frame members 12 by clamp means. The reference bar assembly 16 is mounted on the frame members 12 utilizing conventional square means in order that the reference bar a~sembly 16 may be mounted perpendicular to the frame members 12. The wheel a~semblies 26 provide a means for extending the centerline of the axis of the axles 13, 14 and 20. lt may thus be appreciated that there are provided means for determining alignment of the axles 13, 14 and 20 with respect to the frame members 12 by measuring from a fixed point on the reference bar as~embly to the centerline of the axles on one side thereof and ta~ing a corresponding measurement on the opposite side of the frame members 12 from the reference bar a~sembly 16 to the centerline of the axle~.

Thus, by taking the measurement~ and comparin~ the mea~uremerltE A and A', it can be determined whether or not the ~ 7 ~

driv~ ~xle 13 i8 perpen~icularly ~riented with r~spect to t~e frame member~ 12. Similarly, the orientation of the drive axle 14 and ~he ront axle ~0 may also be determined by comparing measurements B and B' and C and C' respectively.

Referring now to Fig. 1 of the drawings, there are diRclo~ed ~he detail~ of construction o the reference bar assembly 16. The reference bar assembly 16 i~ compri~ed of a ~upport bar 31 which, in the exemplary embodiment, is made from 6quare ~eamless tubing preferably of a corrosion-re6istant material or having a corrosion-resistant co ting thereon. The ~upport bar 31 i8 temporarily affixed to the frame members 12 by means of reference bar clamps 17. A conYentional ~q~are is utilized during the mounting of the ~upport bar 31 to the frame members 12 in order to insure that the ~upport bar 31 i8 perpendicular to the ~rame members 12. The support bar 31 is adapted to extend beyond the frame members 12 on both sides of the truck tractor 11 sliqhtly hort of the first inside wheel of the truck tractor 11. Although the reference bar assembly i~ shown mounted on the rear of the tractor 11, the assembly may be mounted on any convenient place on the frame members 12.

Di~posed in each end of the support bar 31 is telescoping member 18. In the exemplary embodiment the telescoping member 18 is comprised of a square tubing member adapted to be lidably moved within the support bar 31.
Fixedly attached to the outboard end of the telescoping member i8 vertical member 21.

Clamp assemblie~ 19 are utilized to retain the tele~coping member 18 in a fixed positional relationship with r~spect to ~he ~upport bar 31. m e clamp assemblie~ 19, a ~ 8 ~ 0 : ~ more fully di~clo ed in Fig. 4 of ~h~ drawings, are ~dapted to fri~tionally engage the telescoping member 18 by manual rotation of ~he k~urled head 43 of the thread member 42 causing the thread member to be di~placed i~ward of the threaded tab 41 and ~upp~rt bar 31 cau~ing an engagement of the telescoping member 18 between the inner surface of the ~upport bar 31 and the i~ner end of the thread member 42.

It 6hould be noted that two clamp assemblies 19 are u~ed on ad~acent urfaces of the support bar 31 in order to cause the telescoping member 18 to be nested in a corner of ~he inside of the sguare tubing which comprises the support ~ar 31. Thi~ inside corner of the support bar 31 and its adjacent inner surfaces provides a reference ~urface from which the t~le~coping me~ber 18 may be positioned due to the orthogonal relation~hip of the clamp assemblies 19 causing the telescoping member 18 to be disposed proximate to these ~urfaces. The resulting relationship of the telescoping member with re6pect to the support bar 31 provide~ a relatively accurate means for positioning the telescoping member 18 with re~pect to the support bar 31 which means for po~itioning are readily repeatable and tend to negate the clearances and manufacturing errors of the sguare tubing which comprise the ~upport bar 31 and the telescoping member 18.

The telexcoping member 18 has fixedly attached to the outboard end thereof vertical member 21. The vertical member 21 i~ comprisad of a square tubing member preferibly of a non-corro ive material or having a corrosion-resi6tant coating applied thereto. The vertical ~ember 21 i8 perpendicu~arly mounted with respect to the tele~coping member 18 and i~

2~

ad~pted to 61idab1y receiYe measurinq member 22 which may be positioned relative to the vertical member 21 and fixed relative thereto by clamp assemblies 19 which are employed and embody ~he same features as discus ed above. The measuring member 22 is preferably compri~ed of ~quare tubing, preferably of a non-corrosive material or having a corrosion-resistant GOating applied thereto.

Fixedly attached to the lower end o the measuring member 22 i~ horizontal element 23. The horizontal element 23 is perpendicular to the measuring member 22 and adapted to be substantially parallel to the telescoping member 18.

Scribed upon the horizontal element 23 is a line 24 which is scribed on the horizontal element 23 ~ubstantially parallel to the axis thereof in such a manner as to be parallel to the support bar 31 when the telescoping member 18 is clamped to the support bar 31 and the measuring member 22 is clamped to the vertical memher 21. It should be noted that during the scribing of the line 24 upon the horizontal element 23, it is preferable that the line 24 be parallel to the support bar 31 as opposed to being parallel to t~e horizontal element 23 for reasons which will become more fully apparent below.

It may now be appreciated that there has been provided a means for ex ending a reference line perpedicular to the frame members 12 outward from the frame member~ past the outer edge of the drive tires and urther, there has heen provided means for lowering this reference line to a position at approximately the height of the axles 13, 14 and 20. The reference line BO transposed provides a reference line from which mea~urements may be taken as more fully described below.

- lD

R~ferrins ~ow to ~igure~s 5 and ~ of the drawing~, there are shown further details of construction of the wheel assembly 26 employed by the instant inv~ntion. The wheel a6sembly 26 is adapted to be temporarily affixed to the outer edge of the rim~ of the outboard wheels affixed to the axles 13, 14 and 20 in order to provide a means for measuring the ~rientation of the rim with respect to the ground 15 as more fully disclosed below and additionally providing a means for providing a referen~e related to the axi of the axles 13, 14 ~nd 20.

The wheel assembly 26 is comprised of two frame member~ 51 and 52 which include two parallel rod members secured by cro s member ~eans . Di~posed on the frame members 51 and 5~ at one end thereof is cross member 53, which member ~as two orifices th~rein for receipt of frame members 51 and 52. The cross member 53 i~ adapted to filidably engage the frame members 51 and 52 in order to provide a means for moving ~aid cross member parallel to th~ longitudinal axis of the frame members 51 and 52.

Disposed proximate to the cross-member 53 is lower ~upport member 54 which also has two orifices therein for engaging said frame members 51 and 52 in order to provide a slidable movement of the lower support member 54 along the frame member 51 and 52. In addition, the lower support member 54 has locking means 55. The locking mean6 55 is compri~ed of an angled rod-shaped member having one end thereof threaded in order to engage a similarly threaded hole in tke lower ~llp~ort member 54 in proximity to the frame member 51 in order to provide a frictional engagement of the locking means 55 with re pect to the frame member 51 upon 2~
rot~ti~n o~ t~e lQc~ mea~s ~ e lo~ing means ~ thus provides a means for ixing the position of ~he lower support member 54 with respect to the frame members 51 and 52.

Disposed between the frame members 51 and 52 on the S lower ~upport member 54 is cam lever 57 which i~ affixed to and adapted to provide angular movement of the cam member 58 ~æ~ociated with the lower support member 54 and generally dispo~ed between the lower upport member 54 and the cross member 53. The cam lever 57 and its associated cam member 58 are employed to provide a locking mechanism for securing the wheel assembly 26 to the rim 64 as more fully disclosed below.

Centrally di~posed within the cross member 53 i6 upper extension member 62. The upper extension member 62 iB
fixedly attached to the cross member 53 and has one end thereof ~hreaded in order to receive threaded member 63 a~
more clearly ~hown in Figure 6 of the drawings. The threaded member 63, which is of a substantially smaller diameter than the upper extension member 62, is used in conjunction with the end of the extension member 62 to provide a corner contact with the inside edge of rim 64. Specifically, the end of the upper extension member 62 is adapted to contact the outer edge of the rim 64 while the threaded member 63 is adapted to ~imultaneously engage the inner edge of the rim 64. The thread~ of the threaded member 63 facilitate the engagement of the threaded member 63 with the inner edge of the rim 64.
Thi8 engagement is utilized to mount the wheel assembly 26 on the rim 64 as more fully described below.

- 12 ~

Mou~t~d on ~he oppo~it~ ~nds ~ ~he frame m~ers 51 and 52 i8 lower cro~6 member 61. The lower cross member 61 is fixedly attached to the frame members 51 and 52. The lower cros~ me~berc 61 is also ~dapted to fixedly receive the lower extension me~ber~ 65 which are mvunted on the lower cross member 61 proximate to the ends o~ the lower cro~s member 61.
As more clearly shown in Figure 6 of the drawings, the lower extension members 65 have a threaded hole in one end thereof to receive threaded member~ 63 in a manner and for purposes described above in connection with the upper extension member 62. In additioA there is provided a cross bar 66 which is mounted on the outer ends of the lower extçnsion me~ber~ 65 oppo~ite to the ends having the threaded member 63 a~sociated therewith.

It may now be appreciated by one ~killed in the art that there is provided a means for attaching the wheel assembly 26 to the rim of a tire. In operation the wheel assembly 26 ix placed on the rim of a wheel in order to engage the threaded members 63 of the lower extension members 65. The lower ~upport member 54 is then adjusted after releasing locking means 55 in order to position the threaded member 63 of the upper extension member 62 to a position wherein the threaded member 63 of the upper extension member 62 at lea t partially engages the rim 64. The lower ~upport member 54 i 5 then ~5 locked in thi8 po~ition by rotating locking means 55. The cross member 53 ~upporting the upper extension member 62 is ~hen displaced relative to the lower support member 54 by rotation of cam lever 57 causing the cam member 58 to di~place the cros~ member 53 relative to the lower support member 54.
This relative displacement of the cros~ member 53 cau6eæ a further engagement of the threaded member 63 of ~he upper 13 ~

extension member 62 with the rim 64, khereby securely fa~tening the wheel assembly 26 to the rim 64.

There i~ thu~ provided a mean~ for readily affixing the wheel as~embly 26 to the rim of a wheel and imilarly removing ~ame from ~he rim.

Slidably engaging the fr~me member~ 51 and 52 i8 middle cros~ member 71. The middle cros~ member 71 ha~
affixed thereto flange 73. The flange 73 ha~ a square hole therein which extends through the middle cross member 71 and i~ adapted to receive axle refer~nce bar 75. The axle reference bar 75 has a generally ~guare cross ~ection and has - one end thereo pointed t~ fa~ilit~te receipt by the end of the axle 13. The ends of vehicle axles ~onventionally have conical ~haped depression in the ends thereof centered about the central axi~ of the axle as a result of the manufac-turing process~s employed to manufacture the axle. The axle reference bar i8 adapted to have the pointed end thereof coact and be received by the conical depression in the end of the axles to position one end of the axle reference bar 75 ~ubstantially coincident with the centerline of the axle 13.

Flange loc~ing member 74 which i~ comprised of an angularly shaped rod member having one end thereof threaded in order to be received by a ~imilarly threaded hole in the flange 73 i~ utilized to frictionally engage the axle reference bar 75 and temporarily re~trict movement of the axle reference bar 75 with re6pect to the middle cro~s member 71.

The middle cros~ me~ber 71 may be temporarily affixed at a position on the frame members 51 and 52 by middle cross . - 14 ~

member lock 71 which i~ similar in c~nstruction to t~e locking mean~ 55 di cu~sed above.

In operation, after the wheel a~sembly 26 has been affixed to the rim 64, the middle cross m2mber 71 is positioned by the operator to a location wherein the centerline of the axle 13 i~ ~ubstantially coinçident with the center of the ~quare hole in the flange 73 and the middle cr~ss member 71 i~
then locked in thi8 po~ition by rotation of the middle cross member lock 72. The axle reference bar 75 is then inserted - 10 into the ~quare hole in the flange 73 and the middle cross member 71 $n order to cause ~he pointed end thereof to engage the conical depression in the end of the axle 13. The axle reference bar 75 is then locked in position by rotating ~he flange locking member 74.

It may thus be appreciated that there i~ provided a reference member extending outward from the axle 13 that is ~ubstantially coincident with the axis of the axle 13.
Specifically, it should be noted that since th~ pointed end of the axle reference bar 75 engages the conical depression in the center of the end of the axle 13 and the axle reference bar 7S is ~upported by the middle cross member 71 at a posi ion ~ubstantially coincident with the centerline of the axle 13, the axle reference bar 75 will thus provide an extencion of the axis of the axle 13 from which measurements may be taken as more fully de~cribed below.

It may now be appreciated by one 3killed in the art that there have been di~closed means for providing two reference lines from which measurements may be taken in order to determine the alignment of the drive axles 13, 14 and 20 - 15 ~

wi~h re~pect to-the rame member 120 Specifically, it may be appreciated that a measurement may be taken from the axle reference bar 75 mounted on a wheel assembly 26 mounted on each side of an axle to the scribed line 24 of the reference bar ac~embly 16. A~ will be more readily understood by refer-ring to Figure 2 of the drawings, any deviation in the measure-ment~ taken at A and A' will indicate a misalignment of the drive axle 13 with respect to the frame member 12. Similar measurement6 may be taken with respect to axles 14 and 2C in order to check the alignment of the~e axles.

During a t~pical measuring operation, a conven$ional tape mea~ure is employed to measure the dista~ce from a ixed point on the reference bar 75 to the scribed line 24 on the reference bar assembly 16. Conventionally the end of the tape measured would b~ engaged with the upper edge of the reference bar 75 mounted on the wheel assembly 26 and the tape extended to the horizontal element 23 of the reference bar as~embly 16 in order to make a measurement of the distance between the edge of the reference bar 75 and the scribed line 24 on the horizontal element 23. Although the end of the tape measure i8 not at the precise center of t~e axis of the drive axle 13, it may be appreciated that it is the relative measurement that determines alignment and not the absolute measurements thereof.

There has thus been disclosed an apparatus and method for determinin~ the alignment of axles of a vehicle with respect to frame member~ thereof by utilizing a reference fixed relative to the frame ~ember~ and a second reference coinciding with the axi~ of ~he axles i~ order to allow the mea~urement on ~ach side of the vehicle of the di tance from the aXiB of the axle~ to the fixed reference relative to the fr~me i~ order to provide a m~aE~r~ment of the diff~rence between the fixed reference relative to the frame and the axis of ~he axle.

The instant invention can also be utilized to measure the camber angle of the wheels. The level assem~ly 80 may be used i~ conjunction with the wheel a~sembly 26 in order to ~etermine the camber angle of the w~eel.

The level assembly 80 as disclosed in Figure 6 of the drawings i6 comprised of a frame ~1 which is adapted to be used in conjunction with the wheel assembly 26 by mean~ of mounting member 82 which has a generally cylindrically shaped recess therein adapted to receive the outer end of the upper extension member 62. The lower end of the frame 81 is adapted to rest against the cro ~ bar 66. It should be noted that the upper extension member 62 and the lower extension members 65 are of eq~lal length and that the thickness of the cross bar 66 corresponds to the thickness of the bottom of the mounting member 82. Thus the axis of the framr member 81 is parallel to the plane formed by the outer edge of the rim 64 thereby providing a means for readily measuring the angled ori~ntation of the frame 81 and hence the angled orientation of the rim 64 which in turn corresponds to the camber of the wheel.

The frame 81 restæ on the end of the upper extension member 62 by means of mounting member 82. There is, therefore, a tendency for the frame 81 to assume a vertical position relative to the ground with respect to a plane parallel to a pl~n? ~nt~;~;ng ~ edge of the rim 64.

The frame 81 when mounted on the upper extension member 62 and resting against the cross bar 66 will assume a camber angle identical to that of the edge of the rim 64. This camber angle is then read using the level assembly 84.
The details of a typical level assembly are dis-closed in Figure 7 of the drawings. The level assembly disclosed in Figure 7 of the drawing corresponds to level assembly 83 shown in Figure 6 of the drawings. The level assembly 83 is pivotally affixed -to the fraMe 81 by means of pivot mount 90 which is comprised of a nut, bolt and washer combination allowing the level frame 87 to pivot about the pivot mount 90. Fixedly attached to the level frame 87 is level vial 86 having an air bubble therein which is utilized to indicate the level condition of the level vial 86 and its associated level frame 87.
Disposed proximate to one end of the level frame 87 between the level frame 87 and the frame 81 is spring 89 which is utilized to spring bias the level frame 87 about the pivot mount 90. Located proximate to the opposite end of the level frame 87 is adjusting screw 88 which engages threads within the level frame 87 and extends therethrough.
It may be readily appreciated that the level frame 87 may be rotated about the pivot mount 90 by means of adjusting screw 88 by rotating the adjusting screw and causing a relative displacement of the adjusting screw with respect to the level frame 87 wherein the spring 89 causes the end of the adjusting screw 88 to maintain contact with the frame 81 thus resulting in an angular displacement of the level frame 87 about the pivot mount 90. In the exem-plary embodiment an adjusting - 18 ~

~cr~w 8B i~ em~loyed 6u~h ~hat o~e ~ull revolutiDn vf the adjusting ~crew 88 corresponds to a one degree of rotation of ~he level frame 87 ~bout the pivot mount 90. The top of the adju~ting ~crew 88 i provided with gradations which allow the level frame ~7 to be accurately Idisplaced within a fraction of one degree.

It may now be readily appreciated by one ~killed in the art ~hat the camber of the wheel 64 with respect to the ground 15 may be determined by mounting the frame 81 on the upper exten~ion member 82 and allowing the frame 81 ~o assume a substantially vertical position and resting again t cross bar 66. The level assembly 84 is then adjusted to provide a - level condition of the level assembly 84 with the angular displacement required to produce ~uch a level condition corresponding to the camber of the rim 64. It ~hould be noted that the camber of the rim 64 is measured relative to the ground 15. If the ground 15 is not perfectly level, the measurement of the camber will be affected. Accordingly, the slope of the ground 15 is determined by placing ~he frame 81 on the ground in a position parallel to the axis of the axle and measuring, using level as~embly 83, the inclination of the ground 15. This inclination is used to correct the camber measured by the level assembly R4 to determine the actual camber of the rim 64.

It will be apparent to those skilled in the ar~ that variou~ modifications and additions may be made in the instant invention without departing from ~he essential features thereof, which are intended to be defined and ~ecured by the appended claims.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for determining alignment of a vehicle axle having a first and second end with respect to a frame member of said vehicle comprising the step of:
a. measuring a first distance from a point related to the centerline of said first end of said axle to a reference line perpendicular to said frame member;
b. measuring a second distance from a point related to the centerline of said second end of said axle to said reference line perpendicular to said frame member; and c. comparing the measurements of said first and second distances.

2. The method of Claim 1 wherein a tape measure is employed to measure said first and second distances.

3. The method of Claim 1 wherein said reference line perpendicular to said frame member is disposed at approxi-mately the same height as the centerline of said axle.

4. A method for determining the alignment of a vehicle axle having a wheel mounted on each end thereof with respect to a vehicle frame member comprising the steps of:
a. affixing a first reference member to said vehicle frame member;
b. affixing a second reference member to a first one of said wheels;
c. measuring the distance from a point on said first reference member to a point on said second reference member;
d. affixing a second reference member to a second one of said wheels;

e. measuring the distance from a point on said first reference member to a point on said second reference member on said second one of said wheels; and f. comparing the distance from said first measurement with the distance from said second measurement.

5. The method of Claim 4 wherein said second reference member frictionally engages an edge of said wheel.

6. An apparatus for determining the alignment of a vehicle axle of a vehicle having at least one wheel comprising:
a. a first reference means adapted to be fixedly attached to said vehicle;
b. a second reference means adapted to be fixedly attached to said wheel; and c. measuring means adapted to measure the distance between a point on said first reference means to a point on said second reference means.

7. The apparatus of Claim 6 wherein said vehicle has at least one frame member and said first reference means is adapted to be fixedly attached to said frame member.

8. The apparatus of Claim 7 wherein said first reference means is affixed to said frame member by clamp means.

9. The apparatus of Claim 7 wherein said first reference means is mounted perpendicular to at least one frame member.

10. The apparatus of Claim 6 wherein said second reference means includes axle reference means.